A particularly useful method and apparatus for measuring the concentration of enzymatic substrates in sample solutions is described in U.S. Pat. Nos. 3,857,771 and 3,933,593 to James C. Sternberg. In particular, the Sternberg patents describe analyzers and methods for determining initial enzymatic substrate concentrations by measuring the rate at which oxygen is consumed in a chemical reaction including the enzymatic substrate.
While the Sternberg and other similar oxygen rate analyzers provide means for rapidly determining initial enzymatic substrate concentrations, the signals generated in such analyzers and indicative of such concentrations sometimes are quite small. Under such circumstances, it is desired to substantially raise the oxygen rate analyzer's sensitivity, referred to as the signal-to-noise ratio.